We offer the widest product range of low-flow (mass) flow meters and controllers on the market. Numerous styles of both standard and bespoke instruments can be offered for applications in laboratory, machinery, industry and hazardous areas.

Customer satisfaction, innovation and quality of product and service have been the cornerstones of Bronkhorst's success. Based on our experience, innovation and sense of responsibility, a relationship with Bronkhorst assures Performance for Life.

Bronkhorst instruments are used for numerous applications in many different markets. In this section you will find an overview of the main markets for our equipment, illustrated with some typical examples of applications.

Are you looking for technical documentation, are you interested to learn more about the measuring principles of Bronkhorst products, or you do want to get in contact with a Bronkhorst Service Engineer? This section will guide you to the relevant service & support topics.

Thermal Mass flow sensor for gases

Inline / Direct-through / CTA principle

CTA is the abbreviation of Constant Temperature Anemometry, which is also named ‘direct through-flow measurement’ or ‘inline measurement’. Therefore, this principle has no bypass sensor. Amongst various flow measurement techniques the thermal mass flow measurement based on the CTA principle is used for both gases and liquids. Mass flow meters based on the CTA principle cover a wide range of measurement and control applications in almost every industry sector.

Working principle of CTA (Constant Temperature Anemometry) principle, for gases

The Constant Temperature Anemometry - CTA - gas flow sensor consists of two stainless steel probes, the first being a heater and the second being a temperature sensor. A constant temperature difference (ΔT) is created between the probes.

Regardless of the actual flow rate CTA is aiming to keep this delta-T or temperature difference (ΔT) between both sensor pins at a constant level.

The flow rate and the heater energy required to maintain this constant ΔT are proportional and thus indicate the mass flow of the gas. The actual mass flow rate is calculated by measuring the variable power required to maintain this constant temperature difference as the gas flows across the sensor.

Compared to traditional thermal Mass Flow Meters and Mass Flow Controllers with bypass, the construction of the direct measuring CTA principle is less sensitive to humidity and contamination.